Motor fuel composition



3,00 MDTGR FUEL This invention relates to motor fuel compositions and particularly to motor fuel compositions for spark-ignition internal combustion engines adapted to prevent engines stalling due to carburetor icing.

Engine stalling due to carburetor icing occurs most frequently under engine idling conditions and particularly under weather conditions of relatively high humidity and at a temperature below about 60 F. While this problem has been in existence for many years, it has of late become of increased importance because of recent engine design. Most post-war cars are provided with automatic chokes and provide no means for manual operation of the throttle so that operators of such cars are no longer able to regulate idle speeds during warm-up periods to prevent stalling. Furthermore, the idle speed of automobiles equipped with automatic transmissions is rather critical during the warm-up period and the fastest idle rate which may be used is limited to avoid creeping. Another factor in carburetor icing is the high volatility of motor fuels now provided for present-day engines.

' It has been established that the cause of engine stalling in cool humid weather is the formation of ice in the engine carburetor. On such cool moist days, the gasoline evaporated in the carburetor produces a sufficient refrigerating effect to condense and freeze the moisture present in the air entering the carburetor. Fuel vaporization in the fuel carburetor under such conditions can cause a temperature drop in the carburetor of up to 50 F. below that of the entering air; as a result, up to the time of complete engine and radiator warm-up, this drop in temperature causes formation of ice crystals in the carburetor. The maximum refrigeration of the type referred to takes place under conditions of light load operation. As cooling of the carburetor parts takes place, ice begins to form as soon as those parts are refrigerated to a temperature below about 30 F., so that, when the throttle is closed to the idle position, the ice forms, formed or forming in the carburetor, particularly that formed, on the throttle plate and the adjacent walls, closes the narrow air ports, thereby restricting the normal flow of the air to the engine, causing repeated engine stalling. While an engine stalled, because of carburetor icing, can be readily started because the ice formed melts almost immediately due to residual heat from the exhaust manifold, it is highly desired to avoid any stalling due to carburetor icing because of the attendant inconvenience. For example, stalling due to carburetor icing of a car, equipped with automatic transmission, frequently does not occur until the driver is ready to accelerate so that at this most inconvenient time it is necessary to shift the car to neutral, restart the engine and shift back into gear, all of which magnifies the inconvenience of frequent stalls.

It is an object of the present invention to provide a motor fuel for a spark-ignition internal combustion engine which will prevent carburetor icing. Another object of the invention is to provide gasoline for sparkignition internal combustion engines which Will prevent the accumulation of ice crystals on carburetor parts during idling speed and under conditions of light load operation. Still another object of the invention is to provide a hydrocarbon motor fuel composition for spark-ignition internal combustion engines which will prevent engine stalling due to carburetor icing. Other objects and advantages of the present invention will become apparent from the following description thereof.

In accordance with the present invention, the foregoing objects can be attained by incorporating in a hydrocarbon motor fuel composition for spark-ignition internal combustion engines of a carburetor de-icing composition consisting of from about .002% to about .10% of an aliphatic amine salt of an organic phosphate, hereinafter fully defined, and from about .01% to about 3.0% of an alkanol having from 1 to about 4 carbon atoms, such as methanol, propanol, isopropanol, ethanol, l-butanol, 2- butanol, Z-methyl-Z-propanol, and isobutanol, said percentages being based on the total motor fuel composition.

The amine salt of the organic phosphate used in the present invention can be the amine salt of a monoand/ or di-ester of phosphoric acid having the general formula in which R is a hydrocarbon radical and R represents the same or diiferent hydrocarbon radical as R, or hy drogen, at least one of said hydrocarbon radicals being an aliphatic radical of at least about 4 carbon atoms, and Z is an aliphatic amino radical; said R and R hydrocarbon radicals being selected from the group consisting of aliphatic radicals, cycloaliphatic radicals, aryl radicals, alkaryl radicals, aralkyl radicals and mixtures thereof.

Suitable phosphate esters are illustrated by the following: dioctylphosphate, mono-octyl phosphate, di-ocenol phosphate, dilorol phosphate, mono-lorol phosphate, ethyl-lauryl phosphate, octyl-methyl phenyl phosphate, lauryl-cyclohexyl phosphate, methyl-ocenol phosphate, di-Z-ethyl hexyl phosphate, methyl butyl-Z-ethyl hexyl phosphate, 3-methyl phenyl-Z-ethyl hexyl phosphate and the like. Mixtures of monoand di-esters of phosphoric acid can also be employed. For example, a mixture of mono-octyl phosphate and dioctyl phosphate can be suitably used. In the foregoing, the term ocenol defines a radical derived from a mixture of primary aliphatic alcohols containing mostly olelyl alcohol in admixture with C C alcohols. The term lorol defines a radical derived from a mixture of primary aliphatic alcohols obtained by the carboxylic reduction of coconut or palm kernel oils. The mixture contains principally lauryl alcohol in admixture with C C and C alcohols.

The amines which are useful in making the amine salts of organic phosphates as above described, are long chain aliphatic amines having at least one aliphatic group of from about 8 to about 24 carbon atoms attached directly to the amino nitrogen, and includes primary, secondary, and tertiary mono-, di-, and polyamines. Examples of such amines are octyl, decyl, dodecyl, tetradecyl, hexadecyl, and octadecyl amines, hexadecamethylene diamine, octadecamethylene diamine, and amines containing an unsaturated chain such as octenyl, decenyl, etc. can be used. Technical mixtures of amines can also be used; for example, amines corresponding to alkyl alcohols obtained by the catalytic hydrogenation of coconut oil; such amines, which may be termed cocoamines" are mixtures of C C alkylarnines, predominantly C alkylamines.

Particularly suitable amine salts of phosphate esters are commercially available products marketed as Gulf Agent No. 178 which is the cocoamine salt of methyl butyl-2-ethyl hexyl phosphate and Du Pont Rust Preventive No. 2 which is an active kerosine solution of the cocoamine salt of a mixture of mono-octy1 phosphate and dioctyl phosphate.

The de-icer combination of the present invention can be used in any hydrocarbon motor fuel in the gasoline boiling range adapted for use in spark-ignition internal combustion engines. Such hydrocarbon motor fuels Intermediate Winter Initial Boiling Point, F 88 80 10% Recovery, F... 123 108 50% Recovery, F. 210 107 90% Recovery, F. 312 309 End Point, F 373 364 The hydrocarbon motor fuel can contain any of the commonly used additives such as lead alkyl anti-knock agents, e.g. tetraethyl lead, lead scavenging agents, dyes, gum inhibitors, oxidation inhibitors, corrosion inhibitors, spark plug-fouling inhibitors, etc.

The effectiveness of de-icers in preventing engine stalls is determined in a single-cylinder Lauson H2 engine equipped with a downdraft carburetor operated under the following conditions: Air from a CFR ice tower, and having a dry bulb temperature of 3740 F. and a wet bulb temperature of 3437 F. is fed to the carburetor of the engine operating on a test cycle of five minutes at full throttle, 1800 rpm, and five minutes at idle, 1800 rpm. This test cycle is repeated until the engine stalls.

Using, as the base fuel, a winter igrade leaded gasoline containing a commercial antioxidant, corrosion inhibitor and spark-plug fouling inhibitor, and having the following ASTM distillation characteristics:

F. Initial boiling point 80 10% recovery 106 50% recovery 191 90% recovery 302 End point 376 The following samples were subjected to the above de-icer test:

Cs-Cis primary alkylamine salt of a mixture of mono-octyl phosphate and dioctyl phosphate.

Table 1 Percent Im- Sample No. Minutes To provement Stall Over Base Fuel The above data demonstrate the marked superiority of the combination of an amine salt of organic phosphates and an alkanol (Sample 4) as a de-icer over each component alone (Samples 2 and 3) and other known de-icers (Samples 5, 6, and 7).

The effectiveness of the composition of the present invention in preventing and/or reducing engine stalling due to carburetor icing is further demonstrated by the results obtained in the operation of a 6-cylinder 1954 Plymouth automobile engine operated in a speciallyinstrumented cold room. In this test the engine is operated with an intake air temperature of 3540 F. and humidity with continuous air circulation. The engine is started cold and accelerated to 1500 r.p.m. and maintained at that speed for one minute. The engine is then decelerated to idle rpm. and idled for one-half minute. Engine stalling and/or bucking characteristics are observed and recorded; if the engine stalls, it is immediately restarted and run through the described cycle.

The following gasoline compositions were tested under the above conditions:

2 C8-C1s primary alkylamine salt of a mixture of mono-octyl phosphate and dioctyl phosphate.

Table 11 Performance Sample No.

Stalls Bucks The above data demonstrate the superiority of the de-icing composition (Sample 5) of the present invention.

Percentages given herein and in the appended claims are volume percentages, unless otherwise stated.

While the present invention has been illustrated by reference to preferred embodiments thereof, the invention is not be limited thereby, but includes within its Scope such modifications and variations as come within the spirit of the appended claims.

We claim:

1. A spark-ignition internal combustion engine motor fuel composition having reduced engine stalling tendencies due to carburetor icing, comprising a major proportion of gasoline, and to impart de-icing properties to said motor fuel composition from about 0.002% (vol.) to about 0.10% (vol.) of a salt of a C -C unsubstituted aliphatic amine and of a dialkyl phosphate in which at least one of the alkyl radicals contains from about 8 to about 12 carbon atoms, and from about 0.01% (vol.) to about 3.0% (vol.) of an alkanol containing 1 to about 4 carbon atoms, said percentages being based on the total motor fuel composition.

2. A spark-ignition internal combustion engine motor fuel composition having reduced engine stalling tendencies due to carburetor icing, comprising a major proportion of gasoline, and to impart de-icing properties to said motor fuel composition, from about 0.002% (vol.) to about 0.10% (vol.) of a salt of a Cg-C1g primary alkylamine and a mixture of mono-octyl phosphate and di-octyl phosphate and from about 0.01% (vol.) to about 3.0% (vol.) methanol, said percentages being based on the total motor fuel composition.

References Cited in the file of this patent UNITED STATES PATENTS ,522 Hickok et al. Feb. 9, 1954 ,942 Arkis et al. Dec. 13, 1955 2, 89,891 Brandes et a1. Apr. 23, 1957 43 Cantrell et al. Sept. 9, 1958 2,863,742 Cantrell et al. Dec. 9, 1958 62904 Cantrell et al Dec. 9, 1958 

1. A SPARK-IGNITION INTERNAL COMBUSTION ENGINE MOTOR FUEL COMPOSITION HAVING REDUCED ENGINE STALLING TENDENCIES DUE TO CARBURETOR ICING, COMPRISING A MAJOR PROPORTION OF GASOLINE, AND TO IMPART DE-ICING PROPERTIES TO SAID MOTOR FUEL COMPOSITION FROM ABOUT 0.002% (VOL.) TO ABOUT 0.10% (VOL.) OF A SALT OF A C8-C18 UNSUBSTITUTED ALIPHATIC AMINE AND OF A DIALKYL PHOSPHATE IN WHICH AT LEAST ONE OF THE ALKYL RADICALS CONTAINS FROM ABOUT 8 TO ABOUT 12 CARBON ATOMS, AND FROM ABOUT 0.01% (VOL.) TO ABOUT 3.0% (VOL.) OFF AN ALKANOL CONTAINING 1 TO ABOUT 4 CARBON ATOMS, SAID PERCENTAGES BEING BASED ON THE TOTAL MOTOR FUEL COMPOSITION. 